Embodiments of the disclosure relate to a semiconductor device, and more particularly, to a circuit for cancelling offset capacitance of a touch sensor of a capacitive touch screen panel and devices including the same.
Capacitive touch screens may be largely divided into a type using a mutual-capacitance sensing method and a type using a self-capacitance sensing method. In capacitive touch screens using the mutual-capacitance sensing method, an offset capacitance is generally several picofarads (pF) and a signal capacitance is several tens of femtofarads (fF). The offset capacitance may be a capacitance of a touch sensor formed in a capacitive touch screen and the signal capacitance may be a capacitance generated by a touching object like a finger in the touch sensor.
In capacitive touch screens using the self-capacitance sensing method, an offset capacitance is generally several tens of pF and a signal capacitance is several tens of fF. In capacitive touch screens, offset capacitance is significantly larger than signal capacitance. When the offset capacitance is not cancelled, the signal capacitance may not be sensed. Accordingly, the offset capacitance exerts a large influence on the sensitivity of a capacitive touch screen.